• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.208.1-208.1
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• 2010

일일 50톤 처리용량의 도시고형폐기물소각설비의 폐열 보일러에서 생산되는 4.0~6.5 bar의 저압증기를 이용하여 전력을 생산하는 축류식 MSTG설비에 있어서 공급증기압력, 입출구의 압력차이에 의한 발전효율을 비교하고, 저압의 증기의 균질화를 위한 기술분리, 정압유지설비 및 증기터빈의 본체의 기수분리된 증기의 응축효율을 증기공급율, 발전효율별로 비교분석하였다. 공급되는 증기의 압력, 증기터빈의 입출구 압력 차이가 높아짐에 따라, 증기의 응축효율이 증가를 하였으며, 배출되는 증기량에 따른 발전효율의 증가는 없었다. 따라서, 가변적으로 변하는 저압의 증기를 기수분리 및 정압을 유지하여도 증기질의 변동이 없으며 그에 따른 증기의 엔탈피 변화가 없으므로 발전 효율의 향상을 기대하기는 어려웠다.

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.703-707
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• 2001

A performance analysis of a SOFC/MGT hybrid system has been carried out for concept design. Thermo-dynamic models for each component being able to describe electrochemical characteristics and heat and mate-rial balance are proposed. Estimated is the power capacity of a SOFC suitable for the hybrid operation with a 5kW class MGT. Effects of current density and operating pressure are also investigated. Electric efficiency showed weak dependence on operating pressure and current density. It is desirable that the SOFC operates at high current density in manufacturing cost's point of view though operating with high current density slightly decreases the electric efficiency find specific power.

• Laser Solutions
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• v.7 no.2
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• pp.27-38
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• 2004

Laser remelting of surface of cobalt-based hardfacing alloy can eliminate impurities and cracks and improve the wear resistance. In this present study, Stellite ${\sharp}6\;and\;{\sharp}21$ harfacing alloys were remelted by a 3kW CO2 laser. Hardness distribution and microstructures in the laser remelted zone was investigated. Our results showed that in proper laser parameters laser remelted surface of hardfacing alloy had more refined microstructure and more increased micro-hardness than the base material.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1139_1141
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• 2009

Distributed Generation (DG) is predicted to play a important role in electric power system in the near future. insertion of DG system into existing distribution network has great impact on real-time system operation and planning. It is widely accepted that micro turbine generation (MTG) systems are currently attracting lot of attention to meet customers need in the distributed power generation market In order to investigate the performance of MT generation systems, their efficient modeling is required. This paper presents the modeling and simulation of a MT generation system suitable for grid-connected operation. The system comprises of a permanent magnet synchronous generator driven by a MT. A brief description of the overall system is given, and mathematical models for the MT and permanent magnet synchronous generator are presented. Also, the use of power electronics in conditioning the power output of the generating system is demonstrated. Simulation studies with MATLAB/Simulink have been carried out in grid-connected operation mode of a DG system. The control strategies for grid connected operation mode of DG system is also presented.

• Journal of the Korean Society of Safety
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• v.25 no.3
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• pp.28-33
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• 2010

Ni alloy steel is able to use during long time because of good acid and corrosion resistance. So, it's research has focused on developing the alternative alloy which is economically feasible. Recently, consumption of Kovar steel is gradually increased in field of the jet engine and the gas turbine because of its low thermal expansive characteristics. The specimens of Kovar steel(29%Ni-17%Co) contain 0.00%C, 0.03%C, 0.06%C, 0.10%C and 0.20%C, respectively. Ingots are manufactured by VIM(vacuum induction melting furnace) and then specimens are made by automatic hot rolling after heat treatment. Strength of Kovar steel according to carbon contents is estimated by hardness, tensile and impact test. Hardness of the 0.20%C specimen is more improved approximately 14.4% than one of base metal. Its strength increases 32.4% of a base metal, and its impact energy is also enhance 11.5%.

• International Journal of Advanced Culture Technology
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• v.3 no.1
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• pp.101-112
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• 2015

Renewable energy resources play an important part in the world's future. Renewable energy sources have the following components: biomass, geothermal, solar thermal, directs solar, wind, tidal and hydropower. Hydropower is still the most efficient way to generate electricity worldwide. Hydropower projects can contribute as a cheap energy source, as well to encourage the development of small industries across a wide range of new technology; furthermore hydropower systems use the energy in flowing and falling water to produce electricity or mechanical energy. Hydropower systems are classified as large, medium, small, mini and micro according to their installed power generation capacity, as do the following components: water turbines, control mechanisms and electrical transmissions. In this article a review of small hydropower systems has been done on the principles surrounding the fundamentals of hydraulic engineering, the fundamentals of hydrology, identification of sites and economic analysis.

• Plant Journal
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• v.7 no.1
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• pp.40-48
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• 2011

This study shows the comparison between expected and actual capacity factors of a wind farm through wind resource analyzation. The expected capacity factor comes from an 'automatic weather system' run by the Korean national weather service and a 'meteorological mast' run by a project owner. Based on this comparison and analysis, the importance of meteorological mast micro-siting and selection of wind turbine class and type, will be studied along with presenting important implications for wind farm expansion and development.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.05a
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• pp.453-457
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• 2009

Distributed Generation (DG) is predicted to play a important role in electric power system in the near future. insertion of DG system into existing distribution network has great impact on real-time system operation and planning. It is widely accepted that micro turbine generation (MTG) systems are currently attracting lot of attention to meet customers need in the distributed power generation market. In order to investigate the performance of MT generation systems, their efficient modeling is required. This paper presents the modeling and simulation of a MT generation system suitable for isolated operation. The system comprises of a Permanent magnet synchronous generator driven by a MT. A brief description of the overall system is given, and mathematical models for the MT and permanent magnet synchronous generator are presented. Also, the use of power electronics in conditioning the power output of the generating system is demonstrated. Simulation studies with MATLAB/Simulink have been carried out in islanding operation mode of a DG system.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1733-1735
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• 2005

최근의 소형 분산 전원의 보급 필요성의 커짐으로 전력과 열에너지를 동시에 생산, 이용함으로서 종합 에너지 효율이 높고 공해 배출 및 소음 특성이 우수한 초소형 가스터빈 발전 시스템에 대한 수요가 급증하고 있다. 본 논문은 마이크로 가스터빈 시스템과 그 제어장치의 동작 상태를 모니터링 및 제어하기 위한 마이크로 가스터빈 감시 제어장치와 사용자 인터페이스 프로그램을 소개한다. 마이크로 가스 터빈은 초고속(수만$\sim$10만 RPM)으로 회전하여 발전을 하므로 터빈 및 전동기 설계 기술과 더불어 고성능의 제어 시스템을 필요로 한다. 마이크로 가스터빈의 감시 제어 시스템은 터빈, 발전기 및 전력 변환장치를 제어하는 고성능의 DSP 제어장치들과 고속 직렬 통신 방식으로 연결되어 시스템의 제어 및 상태 감시를 위한 최적의 솔루션을 제공함으로서 마이크로 가스터빈의 개발자와 운용자의 보조 역할을 담당한다.

• Journal of Power System Engineering
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• v.17 no.4
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• pp.139-146
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• 2013

Because the magnetic bearing supports levitating body without contact, wear, noise and vibration, it is very useful to high revolution machinery. In this paper we selected ATmega 128, a less expensive and widely used micro controller, for control the magnetic bearing system. And we selected the sampling time and the control gain of PID controller through trial-and-error. The control program of the one board controller utilized lookup table to reduce calculation time, and bit shifting for the integer calculation in instead of floating point calculation. As the results, the controller carried out relatively high speed PID control on sampling time 0.25 ms. At last the rotation test for the magnetic bearing system was carried out by 3 phase induction motor and air turbine.